<template>
  <div>
    <!-- 评论列表 -->
    <div class="cmt-list" :class="{ 'art-cmt-container-1': isShowCmtBox, 'art-cmt-container-2': !isShowCmtBox }">
      <!-- 评论的Item项 -->
      <!-- van-list包裹列表，组件内源码，检测网页滚动事件，判断滚动位置是否快到达内容高度（触底），触发load事件执行，loading为true，底部加载中文字出现，内部认为现在处于加载中状态 -->
      <!-- imm-check作用：让list组件不要上来就检查是否触底 -->
      <!-- 原因：list列表中内容是异步网络请求回来的，标签挂载时，没有高度，list就会判定触底执行一次onload方法 -->
      <van-list v-model="loading" :finished="finished" finished-text="没有更多评论了，请发表评论" @load="onload" :imediate-check="false">
        <div class="cmt-item" v-for="obj in commentArr" :key="obj.com_id">
          <!-- 头部区域 -->
          <div class="cmt-header">
            <!-- 头部左侧 -->
            <div class="cmt-header-left">
              <img :src="obj.aut_id" alt="" class="avatar" />
              <span class="uname">{{ obj.aut_name }}</span>
            </div>
            <!-- 头部右侧 -->
            <div class="cmt-header-right">
              <van-icon name="like" size="16" color="red" v-if="obj.is_liking === true" @click="likeFn(true, obj)"></van-icon>
              <van-icon name="like-o" size="16" color="gray" v-else @click="likeFn(false, obj)"></van-icon>
            </div>
          </div>
          <!-- 主体区域 -->
          <div class="cmt-body">{{ obj.content }}</div>
          <!-- 尾部区域 -->
          <div class="cmt-footer">{{ timeAgo(obj.pubdate) }}</div>
        </div>
      </van-list>
    </div>

    <!-- 评论容器 -->
    <div>
      <!-- 底部添加评论区域 -->
      <div class="add-cmt-box van-hairline--top" v-if="isShowCmtBox === true">
        <van-icon name="arrow-left" size="0.48rem" @click="$router.back()"></van-icon>
        <div class="ipt-cmt-div" @click="toggleShowFn">发表评论</div>
        <div class="icon-box">
          <van-badge :content="totalCount === 0 ? '' : totalCount" max="99">
            <van-icon name="comment-o" size="0.53333334rem" @click="commentClickFn"></van-icon>
          </van-badge>
          <van-icon name="star-o" size="0.53333334rem"></van-icon>
          <van-icon name="share-o" size="0.533333334rem"></van-icon>
        </div>
      </div>

      <!-- 底部添加评论区域 -->
      <div class="cmt-box van-hairline--top" v-else>
        <textarea placeholder="友善评论、理性发言、阳光心灵" v-fofo @blur="blurFn" v-model="comText"></textarea>
        <van-button type="default" :disabled="comText.length === 0" @click="sendFn">发布</van-button>
      </div>
    </div>
  </div>
</template>

<script>
import { commentsListAPI, commentsLikingAPI, commentsIDisLikingAPI, commentSendAPI } from '@/api'
import { timeAgo } from '../../utils/date.js'

export default {
  data() {
    return {
      offset: null, // 偏移量评论ID
      commentArr: [], // 评论列表
      isShowCmtBox: true, // 底部评论容器
      totalCount: '', // 评论总数量（必须后台返回）
      comText: '', // 发布评论的内容
      loading: false,
      finished: false
    }
  },
  async created() {
    const res = await commentsListAPI({
      id: this.$route.query.art_id // 文章id
    })
    console.log(res)
    this.commentArr = res.data.data.results
    this.totalCount = res.data.data.total_count // 总数量
    this.lastId = res.data.data.last_id // 分页

		// 网页打开没有评论，res结果空数组
		if (res.data.data.results.length === 0) {
			this.finished = true
		}
  },

  methods: {
    timeAgo,
    // 点赞/取消点赞
    async likeFn(bool, commentObj) {
      if (bool === true) {
        commentObj.is_liking = false
        await commentsIDisLikingAPI({
          comId: commentObj.com_id
        })
      } else {
        commentObj.is_liking = true
        await commentsLikingAPI({
          comId: commentObj.com_id
        })
      }
    },
    // 显示评论输入框
    toggleShowFn() {
      this.isShowCmtBox = false
    },
    // 评论按钮-点击事件-把第一条评论滑动到最上面
    commentClickFn() {
      // const artcleHeight = document.querySelector('.article-container').scrollHeight
      // // window.scrollTo()是网页进行滚动，设置响应的坐标，就可以让网页滚动刀屏幕的最底端
      // window.scrollTo(0, artcleHeight)

      // 原生标签.scrollIntoView(),让原生的标签滚动到屏幕的最上面
      document.querySelector('.like-box').scrollIntoView({
        behavior: 'smooth'
      })
    },
    // 发布按钮-点击事件
    async sendFn() {
      const res = await commentSendAPI({
        id: this.$route.query.art_id,
        content: this.comText
      })
      console.log(res)
      this.commentArr.unshift(res.data.data.new_obj)
			this.totalCount++
			this.comText = ''
    },
    // 输入框-失去焦点
    blurFn() {
      // 问题：点击发布按钮，发现点击事件不执行-排除代码问题
      // 原因-搞得评论容器-在页面点击发布一瞬间，输入款失去了焦点，被v-if呵呵v-else移除了整个标签
      // 导致点击事件没来得及执行
      // 解决：失去焦点时，变量值，在最后再执行
      setTimeout(() => {
        this.isShowCmtBox = true
      }, 0)
    },
    // 加载更多
    async onload() {
      if (this.commentArr.length > 0) {
        // 请求下一页
        const res = await commentsListAPI({
          id: this.$route.query.art_id, // 文章id
          offset: this.lastId
        })
        console.log(res)
        this.commentArr = [...this.commentArr, ...res.data.data.results]
        this.totalCount = res.data.data.total_count // 总数量
        this.lastId = res.data.data.last_id // 分页
        if (res.data.data.last_id === null) {
          this.finished = true
        }
        this.loading = false
      } else {
        this.loading = false
      }
    }
  }
}
</script>

<style lang="less" scoped>
.cmt-list {
  padding: 10px;
  .cmt-item {
    padding: 15px 0;
    + .cmt-item {
      border-top: 1px solid #f8f8f8;
    }
    .cmt-header {
      display: flex;
      align-items: center;
      justify-content: space-between;
      .cmt-header-left {
        display: flex;
        align-items: center;
        .avatar {
          width: 40px;
          height: 40px;
          background-color: #f8f8f8;
          border-radius: 50%;
          margin-right: 15px;
        }
        .uname {
          font-size: 12px;
        }
      }
    }
    .cmt-body {
      font-size: 14px;
      line-height: 28px;
      text-indent: 2em;
      margin-top: 6px;
      word-break: break-all;
    }
    .cmt-footer {
      font-size: 12px;
      color: gray;
      margin-top: 10px;
    }
  }
}
// 评论-外层容器
.art-cmt-container-1 {
  padding-bottom: 46px;
}
.art-cmt-container-2 {
  padding-bottom: 80px;
}

// 发布评论的盒子
.add-cmt-box {
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100%;
  box-sizing: border-box;
  background-color: white;
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 46px;
  line-height: 46px;
  padding-left: 10px;
  .ipt-cmt-div {
    flex: 1;
    border: 1px solid #efefef;
    border-radius: 15px;
    height: 30px;
    font-size: 12px;
    line-height: 30px;
    padding-left: 15px;
    background-color: #f8f8f8;
  }
  .icon-box {
    width: 40%;
    display: flex;
    justify-content: space-evenly;
    line-height: 0;
  }
}
.child {
  width: 20px;
  height: 20px;
  background: #f2f3f5;
}

// 发布评论的盒子
.cmt-box {
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 80px;
  display: flex;
  justify-content: space-between;
  align-content: center;
  font-size: 12px;
  padding-left: 10px;
  box-sizing: border-box;
  background-color: white;
  textarea {
    flex: 1;
    height: 66%;
    border: 1px solid #efefef;
    background-color: #f8f8f8;
    resize: none;
    border-radius: 6px;
    padding: 5px;
  }
  .van-button {
    height: 100%;
    border: none;
  }
}
</style>
